An interrupt is a mechanism that is used to send a signal to a CPU. This signal results in the CPU stopping (interrupting) its current program and switching to an alternate program that allows the CPU to service that interrupt. Interrupts can be raised for multiple reasons. Some interrupts can be raised just to inform the CPU of the occurrence of an event so that certain bookkeeping can be done. Other interrupts can be raised to inform the CPU of certain failures that require actions by the CPU. As such, all interrupts are not equal and require different levels of service.